Cooling system with automatic circulation of the cooling mixture



Nov. 5, 1940. l. KLElMENoFF COOLING SYSTEM WITH AUTOMATIC CIRCULATION OF THE` COOLING MIXTURE Filed March 22, 1939 2 Sheets-Sheet l NOV. 5. 1940 l. KLEIMENOFF 2,220,413

COOLING SYSTEM WITH AUTOMATIC CIRCULATION OF THE COOLING MIXTURE Filed March 22, 1939 2 Sheets-Sheet 2 L .summummmm!!!v ||||||||||l||lllllllllllll Z figa/726W- f" Patented Nov. 5, 1940 PATENT OFFICE COOLING SYSTEM WITH AUTOMATIC m- OULATIGN 0F THE COOLING MIXTURE Ivan Kleimenofi, Moscow, Union of Soviet Socialist Republics Application March 22, 1939, Serial No. 263,585. In the Union of Soviet Socialist Republics April s claim. (ci. iz-1mV The present invention relates to a refrigerating system in which the cooling is effectuated by means of a battery of cooling tubes through which automatic circulation of cold salt brine l takes place. Such a system is applicable in the iirst place to refrigerator railroad cars, automobiles, but it may be used also in stationary plants especially in those of small capacity.

In refrigerator railroad cars known heretofore 1 the cooling is effected chiey by a mixture of ice and salt which is kept in special tanks or grated pockets provided in the car. The principal drawback of such a type of cooling systems is that it is impossible to attain a temperature low enough 15' to preserve the frozen products from thawing during the journey. Another serious drawback is the impossibility to maintain a strictly uniform temperature in all parts of the room to be cooled.

A third disadvantage relates to the fact that 20 the ice is usually disposed in such a manner that only a portion is utilized in a very small degree for the cooling action. Besides this the pockets or tanks occupy about 25% of the car volume and together with the ice and salt they repre- 25 sent a dead weight which reduces the carrying capacity and the useful volume of the car.

An important improvement as regards the cooling systems for railroad refrigerator cars resides in the use of a battery of cooling tubes which are 80 preferably provided with ribs and in which a continuous gravitational circulation of the cold salt brine takes place owing to the diierence of the specific gravity due to different concentrations of the brine. This circulation is similar to 35 gravitational circulation in the hot-water central heating systems.

For this purpose the car is provided at both ends with ice-containers which extend across the width of the car, and in the upper part of the car 40 is arranged a tank in which the salt is stored.

The two ice-containers are connected with thevv tank by means of ascending and descending pipes connected to the lower ends of the containers. Between one of these pipes and the tank a bat- 45 tery of tubes is arranged, located under the roof of the car. A pipe passing in the lower part of the car interconnects the two ice-containers so that a closed circulation system is formed in which the salt brine is continuously moving ow- 5 ing to the difference of specic weights of the concentrated and the diluted portions of the brine. In order to eliminate the above-mentioned drawbacks it is necessary in the first place to maintain a temperature which remains constant for a considerable period within the room cooled in this manner. 'I'his constitutes the first problem to be solved by the present invention.

For the elimination of the second drawback it is necessary to maintain the same level of temperature throughout the different lparts of the I room. The solution of this problem is an object of my invention.

To solve these problems it is necessary to secure the constancy of the factors which influence the velocity of circulation of the salt brine through the pipes that is to say the constancy of the dierence of the speclic gravities of the liquid in the ascendant and descendant pipes of the circulatory system. 'Ihis result can be attained by maintaining a constant degree of concentration in the brine owing out of the tank charged with salt, and in the brine which returns to the tank. In this case the velocity of flow of the brine through the pipes will remain constant and the cooling temperature will remain constant for a considerable period.

In order to secure a uniform distribution of temperature throughout all parts of the room it is necessary to create in all parts of the car identical cooling conditions. This condition is attained in the tubes of the coolingbattery which all have equal cross-sectional areas and the same velocity of ilow of the brine is established. .As will be explained below, the tubes are arranged according to the invention in such a manner that all circuits formed by the separate tubes of the battery haveequal hydraulic resistances.

Thus the temperature within the car is always constant and is not iniiuenced by the actual amount of ice in the ice-containers so long as some remains therein. The system therefore enables the mileage run to be increased two or three times that possible with known systems before a fresh supply of ice becomes necessary so that the number of ice-supplying stations may be correspondingly reduced.

The arrangement of the cooling battery and the salt-containing tank does not decrease the actual loading capacity of the car as compared with the known type of refrigerating car. This loading capacity is determined by the volume of free space available, and in the car according to the invention the battery is disposed beneath the ceiling and the salt-containing tank is located on the roof outside the car so that the useful volume of the car is not reduced.

In all parts of the car is maintained the same temperature sufiiciently cold for transporting even of frozen berries and fruit.

In order that the invention may be more fully Fig. 1 is a longitudinal section throughthe cin' provided with a cooling section according to this invention.

Fig. 2 is a section taken on the line II-II of Fig. 1, looking from the right side to the left;

Fig. 3- represents a section taken on the line III-III- of Fig. 1 looking from the left side to the right;

Fig. 4 shows the arrangement of the tubes of the battery which ensures the same degree of the cooling effect produced by any separate tube of the battery.

Fig. 5 is a longitudinal sectional view of the tank for receiving salt.

Fig. 6 is a transverse sectional view of the tank for storing the salt.

Fig. 'I is an enlarged view oi!l the lower portion of one of 4the ice containers.

Referring to Fig. l there are two ice-containers l and 2 disposed at both end walls and extending across the width of the car. The containers are filled with ice which is introduced through the kmanholes 3. provided with tightly sealedlids.

The Water formed from the melting ice occupies the lower parts of the containers. An overilow tube provided at each container serves for maintaining a definite level of water therein.

From the lower end of the container I a pipe 5 covered with thermo-insulating material extends upwards and then makes a bend and extends horizontally lengthwise of the car beneath the roof, preferably just along the central axis. This pipe is connected through a valve 6 to the saltcontaining concentrator-tank 1 which is mounted above the roof of the car and is described more fully hereinafter.

The tank 1 is connected through a second valve 8 to the pipe 9 which is connected by a branch tube I0 to the first header II of the battery of ribbed tubes I2 which extend along the whole length of the car beneath the roof aswell as along the upper -part of the side walls of the car as shown in Figs. 2 and 3.

At the opposite end of the car in the vicinity of the ice-container 2 the tubes I2 of the battery are connected to the second header I3 which is provided with a transverse tube I4 to the middle point of which is connected the pipe I5 leading to the lower end of the ice-container 2.

As may beseen from Figs. 2, 3 and 1 the pipes 5 and I5 are connected to the ice-containers in points lying near the same side wall of the car. At the opposite lateral wall of the car a4 return pipe I6 is mounted beneath the wooden grating of the iloor and this pipe connects the tanks I and 2.

The gravitational circulation of the cold salt brine proceeds in the following manner:

Ice is introduced into the containers I and 2 through the manholes 2`and l, and salt is deposited in the tank 1 through the manholes 2 I. After the manholes 3 and 4 are sealed and the entire cooling system is lled with water the manholes 2l of the tank 1 must be sealed. Thereafter the valve 8 must be temporarily closed and the valve 6 is left open. The salt in the tank 1 is gradually dissolved and in the same time owing to diifusion saturates also the liquid contained in the pipe 5. Thereupon the valve 8 is opened. In the circulation circuit Aso formed the concentration of the understood and carried into eifect it is described salt in the brine contained in the pipe 5 is greater than in the pipe I5, sov that a difference of specinc gravities and consequently the difference of the weights of the liquid columns in these pipes arises'and the liquid begins to iiow continuously formed from the melting ice and becomes diluted so that its concentration decreases and its temperature is reduced at the expense of the melting ice. Then the liquid flows from the container I through the pipe I8 into the lower part of the container 2, where the brine becomes still more diluted and cooled. then upward through the pipe Il, through the battery of tubes I2 and thence through the tube Il), the pipe 8 and the valve 8 back to the tank 1.

The circulation thus established continues as long as some salt remains in the tank 1 and some ice in the containers I- and 2.

The diluted brine which Aowing to the thawing of ice gradually accumulates in the ice-containers above a definite level (shown in Fig. l) ilows out through overfiow tubes 22 provided withvalves 23 which play the role of hydraulic seals. It is suicient to have such a tube in one of the containers I or 2. The overflow tube 22 is connected to the ice container above the point where tubes 5 or I5 are connected to the corresponding container so that these tubes 5 and I5 are always beneath the level of the liquid.

The velocity of circulation of the brine in the system may be as highas 1 meter per second and even more.

In the case when the salt is consumed before all ice has melted and if it is required to supply fresh salt the valves 6 and 8 must be closed prior to opening of the manholes of the tank 1. The tank 1 must always be iilled to the brim with salt and brine.

Under thev conditions above described the cooling system operates at pressure .below atmospheric. When it is desirable to operate the system at atmospheric pressure the manholes 2I of the tank 1 must remain open and the overflow tubes closed. In other respects the action of the system remains unchanged.

In order that the concentration of the brine entering from the tank 1 intoA` the pipe 5 should remain constant regardless ofthe amount of salt in the tank 1, this tank is arranged according to the invention in the following manner.

In the lower part of the tank 1 opposite the pipe 9 there is an included partition I1 as shown in Figs. 1 and 5 mounted transversely in clou contact with both sides of tank 1 leaving only a narrow slit at the bottom of the tank for the 4 passage of liquid. Opposite the pipe 5 there is another transverse inclined partition I8 which engages the bottom of the tank 1. Above the partition I8 an inclined bafile I8 is arranged and the brine can flow only over the upper edge of the partition I8. Between the partitions I1 and I8 are a series of slightly inclined longitudinal plates 20 as shown in Figs. 5 and 6 having their upper edges bent downwards. These plates rest with their lower edges on the bottom of the tank 1 and are shaped at the ends to fit against the inclined partitions I1 and I8 thus forming a series of longitudinal channels in the tank 1. In this manner the plates 20 form a sort of grating.

The salt arranged on the top of this grating falls through the slots of the grating to the bottom. of the tank 1, but owing to the bent upper 7 edges of the plates 20 there remain passages unlled with solid salt through which the liquid iiows continuously from the slit under the partition I1. After the dissolution of the salt a further portion of salt falls through the slots of the grating.

Thus the amount of salt lying upon the grating represents a reserve and only that portion of the salt which falls on the bottom of the tank becomes dissolved and the same passage is always left free for the ow of liquid which carries this portion of salt away. It ensues that the brine owing out of the tank has always practically the same degree of concentration regardless of the amount of the remaining reserve salt until all salt becomes consumed. As it has been indicated above, the constancy of the concentration ensures the constancy of the cooling temperature during the operation'.

To ensure a uniform temperature throughout the Whole room to be cooled the battery consisting of separate ribbed tubes .I2 is arranged in the following manner:

At a given degree of theV concentration and the salt brine entering into the battery the temperature of any of the tubes depends upon the exchange of heat between the brine passing through the tube per unit of time and the surrounding air. A

To obtain the equality of temperature of all .tubes of the battery it is necessary that all these tubes should represent equal resistances to the flow of the liquid.

According to the invention this result is attained by the arrangement shown in Fig. 4,.in which the pipe I5 `feeding the brine to the battery and the discharge pipe I0 are connected to the headers of the battery in such a manner that the path of the brine through all tubes I2 has the same length. To this end the header II has the form of a single tube to which are connected parallel tubes I2 of the battery and thesecondheader consists of a similar tube I3 to which are con- 45 nected the parallel tubes I2 and of a transverse tube I4 which forms a closed' ring together with the tube I3.

The pipe I5 which feeds the cold salt brine to the battery I2 is connected to the middle point 50 of the tube I4 so that the-brine enters into the header I3 from both ends and the pipe I0 through which the brine returns into the tank 1 is connected to the middle point of the header II having both its ends closed. 4,

It may be seen from Fig. 4 that the length of the path of the brine between the point where the pipe I5 is connected to the tube I4 and the point in which the pipe II) is connected to the middle of the header I-I is equal-for any one of 60 the tubes I2.

As a result the hydraulic resistances opposing the ow of liquid through the tubes of the battery are strictly equal, and as a consequence the velocity of the flow is the same in all tubes so 65 that the rate of the heat exchange between any consequently at a given constant temperature of of the tubes of the battery and the airwithin the room to be cooled will be equal.

What I claim is:

1. A car cooling system having automatic gravitational circulation of. cold salt brine Vcomprising, ice containers disposed at both ends' of the car, a tank for receiving a supply of salt mounted on the roof of the car, a battery of cooling tubes disposed beneath the roof and along the upper part of the side walls of the car, headers connecting said tubes in parallel, a pipe connecting the salt tank with the lower portion of one of the ice containers, a pipe connecting the containers with each other, means for maintaining a constant degree of concentration of brine flowing from the tank for lmaintaining a constant temperature dur/ing operation of the cooling system, means for maintaining a uniform distribution oi temperature throughout all parts of the space to be cooled including pipes connecting the two headers of the battery with an outlet of the tank and with one of the ice containers in such a manner that the hydraulic resistancesto the flow of the brine through any of the tubes of the battery is equal.

2. A car cooling system provided with automatic gravitational circulation of cold salt brine comprising an ice container disposed adjacent each end wall of the car, 'a tank f or storing a salt supply, a battery of cooling tubes, pipes connecting said tank with an ice container and the battery, means for maintaining a constant degree of concentration of the brine flowing through the tank consisting of a grating arranged at the bottom of the tank and comprising a plurality of plates disposed in the direction of movement of the brine through the tank, said plates being inclined so that particles of salt can move to the bottom of the tank without obstructing a free passage of the liquid under said bent edges, partitions disposed opposite the pipes connected to the tank for preventing a current of brine passing through the tank from entraining particles..

maintaining a constant degree of concentration of A the brine owing through the tank, two headers, said battery tubes being connected in parallel to the two headers, a transverse tube connecting both ends of one header so as to provide a closed ring, one of said pipes feeding the salt brine to the battery being connected to the midpoint of said transverse tube so that the brine enters the header from both ends, means closing the ends of a second header, a discharge pipe connected to the middle portion of said second header so that the velocity of flow of the salt brine through all of the tubes of the battery is the same.

y IVAN OFF. 

